Since the prevalent use of the 3rd signal light device for automobiles has been very popular, its object is strongly to warn the drivers of oncoming automobiles trailing the user's car, so that these drivers can react in time in order to take proper measures to play safe for both parties. This has the function of giving strong signals to the drivers in the rear. However, the conventional signal lights of various types have a fixture base in a fixed form which once fixed, cannot be adjusted to adapt to the actual needs thereby creating the greatest defect.